Flammable methane continues to bubble up from the ground in 15 to 20 spots on the Leightons' property.

Becky LettenbergerNPR

Mike and Nancy Leighton's problems began on May 19, just as Mike was settling in to watch the Preakness Stakes. A neighbor in Leroy Township, Pa., called Mike and told him to check the water well located just outside his front door.

"I said, 'I'll be down in 15 minutes.' I wanted to see the race," Leighton said. But as the horses were racing, Leighton's well was overflowing. Typically, there's between 80 to 100 feet of head space between the top of the well and its water supply. But when Leighton went outside, the water was bubbling over the top.

Down the road, Ted and Gale Franklin's water well had gone dry. When water started coming out later that week, the liquid was "black as coal," according to Gale.

Since then, both families have been dealing with methane-contaminated water supplies, as well as dozens of mysterious, flammable gas puddles bubbling up on their properties.

Pennsylvania's Department of Environmental Protection blames a nearby hydraulic fracturing, or fracking, operation. It says methane gas has leaked out of the well, which is operated by Chesapeake Energy, and into the Leightons' and Franklins' water supplies.

The danger goes beyond contaminated water. In a letter to both families detailing test results and preliminary findings, state regulators wrote that "there is a physical danger of fire or explosion due to the migration of natural gas water wells." Chesapeake has installed ventilation systems at the two water wells, but the letter warns, "it is not possible to completely eliminate the hazards of having natural gas in your water supply by simply venting your well."

Nancy Leighton said the letter made her "a little nervous," pointing out that both families heat their homes with wood stoves and plan to do so this winter, regardless of whether the gas leaks have gone away.

"What are we going to do? We don't have any other options," Gail Franklin says.

A Methane Gas Express Elevator

So how did this happen?

The whole thing gets a bit confusing, because over and over again, the drilling industry has said fracking hasn't been linked to water contamination. Yet, here's a case where the state says a nearby natural gas well is to blame.

Here's why they're both right.

To frack a well, drillers crack up shale rock with explosives, then flush gas out of the ground with millions of gallons of fluid. For a long time, the fear has been that the chemicals are shot deep underground, then they and the gas find a way to seep back up a mile through the rock and the water supply.

That hasn't been conclusively documented, but what has been proven is something much more basic, and closer to the surface. It's not the technique of fracking — it's the pipe the gas uses to go from point A to point B that can be a problem.

Penn State University geologist David Yoxtheimer has been studying this issue, which is called methane migration. He explained that when a well is leaky, it becomes a methane gas express elevator. "Gas wants to migrate up," he said. "It's lighter. It's less dense. It finds itself trapped in these shallower, more porous formations. And during the drilling process, you can go down through these shallow formations, and as you're drilling through, suddenly you've created a conduit for those gases to escape."

A shoddy cement job is usually what's to blame. Gas wells are lined by a series of steel pipes surrounded by cement. And if the cement pour is rushed or poorly done, methane is going to get out of the well and into the ground. That's what state regulators say happened in 2009 in the same northeast Pennsylvania county where the Leightons and Franklins are currently dealing with stray gas.

'We Want Things Fixed'

Pennsylvania's Department of Environmental Protection fined Chesapeake Energy $900,000 for contaminating 16 families' water supplies. The company disputed the state's conclusion, but agreed to the fine — the largest environmental penalty in Pennsylvania history.

Since then, Pennsylvania regulators put much tougher drilling standards in place, in order to minimize methane leaks.

They mandated higher-quality cement and pipes in gas wells, among other changes. Chesapeake spokesman Michael Kehs said the company has improved its standards. He says the problem affecting the Leightons and Franklins is an "isolated incident," adding, "in this particular case there was a unique problem with a particular piece of equipment that was highly unusual."

Chesapeake is paying for water filtration devices at both families' homes, and in a statement said the malfunction that created the leak "has been identified and corrected. The surface expressions of methane have dramatically abated and are almost gone."

But Mike Leighton, who still has bubbling puddles in his yard, said he's fed up. "The newspapers keep minimizing the damage here, but it's here," said Leighton, pointing out bubbling gas puddles on his property. "And people think we're radicals, but we're not. We're just upset about the condition of our property, and we want things fixed.

"I want my real estate back to where it was before," he says. "And right now, it ain't worth dirt."

Amy Emmert, a policy adviser with the American Petroleum Institute, maintains that the leaky wells are few and far between. "A typical natural gas well is constructed with 3 million pounds of steel and cement," she said.

Still, it only takes one small hole, or one faulty piece of equipment, or one weak chunk of cement, to create problems on the surface.

This story is part of the StateImpact Pennsylvania project. StateImpact is a collaboration between NPR and member stations examining the effect of state policy on people's lives.

Copyright 2014 NPR. To see more, visit http://www.npr.org/.

Transcript

(SOUNDBITE OF LIQUID BUBBLING)

STEVE INSKEEP, HOST:

Wow, what a sound - the sound of bubbles popping up in water near a fracked natural gas well in Pennsylvania. State regulators say methane gas has leaked out of the well, and it's fouled water supplies. The gas industry insists hydraulic fracturing has never caused water problems, and technically, they are right. The process of fracking itself may not be to blame, but that does not mean the industry is off the hook. Scott Detrow of member station WITF visited Leroy Township, Pennsylvania to explain why.

SCOTT DETROW, BYLINE: Mike Leighton's problems started on May 19th, just as he was settling in to watch the Preakness Stakes. A neighbor called and told him to check his water well.

MIKE LEIGHTON: I went out. You can hear my well just bubbling. You know, I got 80 to 100 foot of headspace, and the water actually bubbled up out of the top of that well.

DETROW: Gale and Ted Franklin live a couple hundred yards away. Their water well had a different reaction.

TED FRANKLIN: It was black.

GALE FRANKLIN: Oh, black as coal. It was awful.

DETROW: And had that ever happened before?

FRANKLIN: No, no.

FRANKLIN: No, no.

DETROW: Regulators ran some tests and said yes, a nearby fracking operation is to blame. They say gas has been leaking out of the well owned by Chesapeake Energy. The well is located about a half-mile from where the Leightons and Franklins live. Both families recently received a certified letter from state inspectors, which Nancy Leighton reads to me.

NANCY LEIGHTON: (Reading) It is the department's recommendation that all water wells should be equipped with a working vent. This will help alleviate the possibility of concentrating these gases in areas where ignition would pose a threat to life or property.

DETROW: In other words, you've got flammable nature gas in the air. So they're saying you should vent your well, but that won't eliminate all the problems.

LEIGHTON: Right. Right.

DETROW: How's that make you feel?

LEIGHTON: Well, you're a little nervous.

(LAUGHTER)

LEIGHTON: We heat our house with wood, too, by the way.

(LAUGHTER)

LEIGHTON: We all heat our houses with wood.

DETROW: Chesapeake Energy is providing the families with equipment to clean out their drinking water. But that won't stop methane gas from bubbling out of the ground in dozens of puddles on their properties.

(SOUNDBITE OF BUBBLING)

DETROW: OK. Over and over again, you hear the drilling industry say fracking has not been linked to water contamination. But here's a case where the state says, yes, the well's to blame. So what's going on here?

It turns out, they're both right. Here's why: to frack a well, drillers crack up shale rock with explosives, and then flush gas out of the ground with millions of gallons of fluid. For a long time, the fear has been that you shoot these chemicals deep underground, and then the chemicals and the gas find a way to seep back up a mile through the rock and into the water supply. Well, that has not been conclusively documented. But what has been proven is something much more basic and closer to the surface. It's not the technique of fracking. It's the pipe the gas uses to go from point A to point B that can be a problem.

Penn State University geologist David Yoxtheimer has been studying this. He says when a well is leaky, it becomes a methane gas express elevator.

DAVID YOXTHEIMER: Gas wants to migrate up. You know, it's lighter. It's less dense. And it finds itself getting trapped in these shallower, more porous formations. During the drilling process, you can go down through these shallower formations, and as you're drilling through, suddenly you've created a conduit for those gasses to escape.

DETROW: A shoddy cement job is usually what's to blame, here. Gas wells are lined by a series of steel pipes surrounded by cement. And if the cement job is rushed or poorly done, methane is going to get out of the well and into the ground.

Chesapeake Energy is responsible for one of the most high-profile methane leak problems. Last year, the company was fined $900,000 for faulty cementing that contaminated 16 Pennsylvania families' water supplies. Since then, Pennsylvania regulators put much tougher drilling standards in place, in order to minimize methane leaks. They mandated higher-quality cement and pipes in gas wells, among other changes.

Chesapeake spokesman Michael Kehs says the company has improved its standards. He says the problem affecting the Leightons and Franklins is an isolated incident.

MICHAEL KEHS: In this particular case, there was a unique problem with a particular piece of equipment that caused a pressure buildup that was highly unusual.

DETROW: But Mike Leighton, the guy who still has bubbling puddles in his yard, says he's fed up.

LEIGHTON: The newspapers keep minimizing the damages here, but it's here. And people think that we're radicals, and we're not. We're just upset about the condition of our property, and we want things fixed. I want my real estate back to where it was before. Right now, it ain't worth dirt.

DETROW: Amy Emmert, a policy advisor with the American Petroleum Institute, maintains the leaky wells are few and far between.

AMY EMMERT: A typical natural gas well is constructed with three million pounds of steel and cement.

DETROW: Still, it only takes one small hole, or one faulty piece of equipment, or one weak chunk of cement to create problems on the surface. For NPR News, I'm Scott Detrow.

INSKEEP: That report came to us from State Impact, a collaboration of NPR and local member stations, a collaboration that explores how state issues affect American lives. Transcript provided by NPR, Copyright NPR.